IMO, it's very likely price. I've have become more skeptical of these rankings though. Of late, they can be skewed by sponsorships. While a standard MIL reticle S&B PM2 is priced closely to the ATACR-F1, the Nightforce can be had with one of the sophisticated reticles like the TreMor. To get this level of reticle in the S&B the cost difference can be $1-2000 higher. I think PRS places very high demands on the scope! I haven seen a NF-F1 or S&B fail at a match. Most match failures I have seen(with myself included) were Vortex Gen2's and AMG's. Fortunately service/turnaround with Vortex is excellent, but this doesn't help with the DNF. My current scopes are a NF-F1 and S&B PM11.